Year % 1996 25.13 1997 25.14 1998 25.14 2000 24.98 2001 24.98 2003 24.04 2006 24.04 2008 22 2009 22 2010 22 2011 22 2012 22 2013 22 2014 21.95 2015 21.95 2016 21.95 2019 21.76 2020 21.76 2021 21.76